Uniform tension maintaining device



O 1953 H. LUNGSTROM UNIFORM TENSION MAINTAINING DEVICE Filed July 26, 1949 3 Sheets-$heet l JNVENTOR.

Nov. 3, 1953 H. LUNGSTROM UNIFORM TENSION MAINTAINING DEVICE 3 Sheets-Sheet 2 Filed July 26, 1949 TTORNE Y.

NOV. 3, 1953 H,'| UNGSTRQM 2,657,866

UNIFORM TENSION MAINTAINING DEVICE Filed July 26, 1949 4 3 Sheets-$heet 3 llllH llllllllllhllllllll Patented Nov. 3, 1953 UNITED STATES PATENT OFFICE UNIFORM TENSION MAINTAINING DEVICE Henry Lungstrom, Lindsborg, Kans. Application July 26, 1949, Serial No. 106,888 6 Claims. (01. 242 -11) This invention generally relates to improvements in mechanisms for spirally wrapping strip material on elongated objects as a protective or reenforcing covering for same as, for example, mechanisms for spirally wrapping protective strip material about electric conductors or cables for insulating and waterproofing same; the invention being adapted for various other uses among which are uses in apparatus and devices for spirally winding flexible strip material on mandrels from which the spirally wound material with overlapped convolutions may later be removed in tubular form.

The present invention is particularly adapted for use as an improved wrapping mechanism in apparatus employed for applying a protective priming coat of paint on gas and oil pipe lines and then spirally wrapping the coated pipe with protective strip material fed from one or more reels while the apparatus is supported on and progressively moved along the extended pipe line or, in other instances, where the apparatus is stationary and the pipe is moved through the apparatus.

It is among the objects of the present invention to provide an improved mechanism for spirally wrapping flexible strip material which is fed from a single reel or simultaneously from two reels, on an elongated object, such as an elongated pipe line, and during the spiral wrap ping of the strip constantly maintaining a uniform tension on the unwound portion of the strip; the improved mechanism being particularly adapted for comparatively simple installation on presently employed pipe wrapping apparatus, using a ring type power-driven sprocket, as an improved mechanism having desirable advantages over present mechanisms in more eflicient application of the strip material, in its low cost of manufacture, and low cost of installation.

The various features of novelty whereby the present invention is characterized will hereinafter be pointed out with particularity in the appended claims; but, for a full understanding of the invention and of its objects and advantages, reference may be had to the following detailed description taken in connection with the accompanying drawings exemplifying a preferred embodiment of the invention which is now considered to be the mode of applying the novel principles of the invention.

An appropriate and practical exempliflcation of the invention is found in its adaptation to through one of the two strip-carrying reels emand embodiment in a mechanism for spirally wrapping flexible strip material on gas and oil pipe lines and, therefore, the accompanying drawings illustrate the improved mechanism as a part of well known apparatus now commonly employed for spirally wrapping protective strip material on extended pipe lines before their underground installation. I

In the accompanying illustrative drawings, in which like reference characters designate like or corresponding parts and members,

Fig. 1 is a front elevational perspective view of a pipe wrapping mechanism embodying the present invention; I

Fig. 2 is a rear view of one of the reel carrier plates showing the improved new mechanism for constantly imparting a uniform tension to an unwound portion of the strip material as it unwinds from its reel during spiral wrapping of same about the elongated pipe;

Fig. 3 is a front or opposite view of the reel carrier plate shown in Fig. 2;

Fig. 4 is a plan view of the reel carrier plate shown in Fig. 2 as viewed in the direction of the arrows of line 4-4 of Fig. 2 and showing a roll of strip material and reel therefor and a pair of elongated rollers for guiding the strip of wrapping material as it is unwound from the reg;

Fig. 5 is an enlarged longitudinal section through the relatively fixed guide roller;

Fig. 6 is an enlarged longitudinal section,

ployed in the illustrated apparatus, taken on line 6-6 of Fig. 3;

Fig. 7 is a sectional view through one side of one of the reels showing method of expanding the reel axially for reception thereon of a roll of material of increased width;

1 Fig. 8 is a front elevational view of the sprocket wheel on which the two reels are mounted;

Fig. 9 is a side view of the sprocket wheel shown in Fig. 8 as viewed in the direction of the arrows of line 9-9 of Fig. 8;

Fig. 10 is a horizontal section taken on line l0l0 of Fig. 8 showing a side view of one of the connection lugs on the sprocket wheel to which one of the reel carrier plates is fastened.

Fig. .11 is anenlarged cross-section takenon line I l-H of Fig. 2, showing the bifurcated connection arm which is secured to the inner or rear end of each reel spindle.

In the attached drawings, only that portion of a pipe wrapping machine is shown which is operatively related and connected to the pipe wrapping mechanism and, as shown inFigs. 1, 8 and 9, the parts of the machine shown include a frag- 3 ment of the machine structure designated by numeral I5 on which are supported a drive sprocket l6 which is keyed to a prime-moverdriven shaft l1.

The power-driven sprocket It has trained over it drive chain It which imparts rotation to a comparatively larger driven sprocket is which is of the ring type design to permit passage through its center of the pipe to be wrapped designated by numeral 20. The ring sprocket I3 is shown as made in two half sections bolted together, as at 2|, and rotatably supported on a plurality of circularly spaced rollers 22 which are suitably carried on the machine structure l5.

A suitable adjustable chain tightening sprocket 23 is also supported on the machine structure as shown in Fig. 1.

All of the above elements are old and employed in many presently used pipe wrapping apparatus.

The driven sprocket I3 is provided with a pair a of lugs 24 which extend axially outwardly from diametrically opposite portions of the rear face of the sprocket 19. These lugs 24 may be cast integrally with the ring type sprocket or they may be secured thereto in any suitable manner as by welding and each lug 24 is provided with a pair of holes 24 and 24.

In the illustrated pipe wrapping apparatus, two wrapping mechanisms are shown supported on and secured to the lugs 24. The two mechanisms are both of like construction and are generally designated by numeral 25.

Since the two mechanisms 25 for spirally wrapping strip material on the pipe are of like construction it will suffice to describe in detail only one of them.

Each mechanism 25. as generally shown in assembled form in Figs. 1, 2, Band 4, consists of a carrier plate 26, preferably of oblong shape with rounded ends and parallel side edges, which plate functions as a mounting plate for the operative elements and the reel carrying the roll of strip wrapping material. I

Each mechanism is supported on a spindle 21 the rear end of which, designated by numeral 21', extends through an opening in the reel carrier plate 25 into a sleeve portion 23 which is formed preferably integrally with the bifurcated connection arm 23. A suitable key]! rigidly secures the arm 28 and its sleeve 28 against rotation relatively to the spindle end 21* and the sleeve portion of the arm 23 is adjustably rotatably mounted within the supporting sleeve 33 which in the present instance is shown as welded to the rear face of thecarrier plate 25.

The bifurcated portions of the connection arm 23 are provided with transversely aligned openings consisting of a round hole 23- and an elongated arcuately shaped hole 28'{ the longitudinal centerline of which is on a radius whose center is the center of hole 28 the connection arm 23 being adapted to embrace, between its bifurcated portions, the lug 24 with the hole 28 in registration with the lug hole 24' and the slotted hole 23 in registration with the lug hole 24 and bolts passed through these registering holes secure the entire mechanism 25 to the rotatable sprocket H for revolution about the pipe 20.

As more clearly seen in Fig. 6, the spindle 21 extends through the carrier plate 23 and through the circular plate portion 3i? of the brake drum 3| into the bore of the cast hub 32 wherein the spindle is decreased in diameter, as at 21", to fit snugly into an extending bore of reduced diameter whereby the shoulder 21' of the spindle abuts with the angularly faced offset formed between bores of different diameters.

The bore of reduced diameter containing the spindle portion 21 constitutes an intermediate bore the outer end portion of which is enlarged in diameter and interiorly screw-threaded as at 33. The spindle portion 21 of reduced diameter terminates very slightly beyond the plane of an annular shoulder 34 formed between the intermediate bore portion and the enlarged screwthreaded bore portion 33. A perforated washer 35 is mounted on the end of the spindle portion 21 by a screw 38. The washer 35 is only loosely held against the shoulder 34 while retained by screw 36; this arrangement permitting the hub 32 to rotate about the spindle 21.

A roll 52 of convoluted strip wrapping material, such as bituminized paper or felt, or other electrically nonconductive and acid resisting strip material, or a fabric of glass fiber, is mounted upon a reelcomposed of two similar axially spaced plate members 40 each consisting of an annular plate 43 formed with an integral centrally disposed axially extending cylindrical sleeve portion 40 having an inside diameter adapted to receive therein the cast hub 32.

I The reel plate members 43 are mounted upon the hub 32 in relatively oppositely disposed posi tions with the sleeves 43 facing each other and constituting opposed cylindrical seats for the roll of convoluted strip material; each member preferably having welded to the outer face of the annular plate portion 40' a lug 4| which is adapted to be seated in a recess 42 within the peripheral portion of the flange 32' whereby the reel inner plate member 40 is operatively interengaged with the hub 32 for rotation with it and the brake drum 3|.

The convoluted strip of Wrapping material is confined between the reel plate members 40 which are securely retained on the hub 32 by means of a wedge-action keeper consisting of a cylindrical head 43 having a threaded extension 43 in screw-threaded engagement with the threaded bore 33 within the outer end of the hub 32; the head 43 being provided with a transverse slot 43" and a pin 45 extending transversely through the slot 43 and through an elongated slot 44' in a wedge bar 44 which is slidably mounted in the slot 43 of the head 43. The width of the wedge bar 44 is preferably very slightly less or at most equal to the diameter of the head 43. Due to the slot 44 being disposed angularly to the long axis of the bar 44, the bar 44 will become wedge-locked with pin 45 when it is moved longitudinally in the slot 43 against the outer side face of the outer plate member 40 in the position shown in Fig. 6.

To permit insertion of a new roll of strip material upon the reel, the outer plate member 43 may be slidably removed from the hub 32 simply by moving the bar 44 upwardly (as viewed in Fig. 6) to its release position shown in full lines in Fig. 7 and then turning it about the pin 45 into alignment longitudinally with the axis of the head 43 whereupon both reel plate members 43 may be slidably removed from the hub 32 to permit mounting between them of a new roll of strip material upon hub 32.

The flange 31 of the brake drum 3| is ro tatable about a brake shoe 31 carrying a brakelining 3B engageabie with the inner circular face of the flange 3|" for frictionally braking therotation of the brake drum 3!; the brake shoe 31 being suitably mounted on the outer face of the carrier plate 26, as at 39.

A short brake actuating shaft 46 rotatably supported in plate 26 extends inwardly of the brake drum 3| and terminates therein in an integral brake-releasing cam 41 which is in operative engagement with the brake shoe 31. I

The brake shoe 31 is normally maintained 1n braking position by means of a spring-pressed brake actuating pin 48 thereby frictionally retaining the brake drum 3| together with the hub 32 and the inner reel plate member 40 against free rotation about the supporting spindle 21 and, since the roll of wrapping material is confined by friction between the reel plates 48 by means of the wedge bar 44, the roll of strip material is therefore also retained against' free rotation about spindle 21 by means of the brake actuatin pin 48.

The brake actuating pin 48, which is constantly in engagement with the free end of the brake shoe 31, and the coil spring 49, which constantly exerts pressure against the pin 48, are carried in a housing 50 which is suitably rigidly supported on the plate 26 within the brake drum 3|; the pressure of the spring 49 against the pin 48 being adjustably variable by a screw 5|.

As more clearly disclosed in Figs. 1, 3 and 4, the unwound portion 52 of the strip of wrapping material, which extends from the roll 52, is trained over guide rollers 53 and 54 and secured to the pipe 28. The guide roller 53 is mounted on a shaft 55 which is securely mounted against displacement on plate 26. The roller 54 is rotatably mounted on a shaft 56 carried on the free end of a pivotal arm 51 which is secured to one end of the pivot shaft 58 rotatably carried on plate 26. The opposite end of shaft 58 extends through plate 26 and at rear side of the reel carrier plate 26 is rigidly secured to the pivotal end of the pipe wrapping strip tens on control arm 59 which is operatively link-connected to the brake control arm 68 by preferably a helical spring 6| one end of which is adjustably selectively hook-connected to arm 58 in one of the several holes 59 therein. The opposite end of spring 6| is also adjustably selectively connected to arm 60 in one of the several holes 60 therein.

The pivotal end of the brake control arm 60 is securely connected to the brake actuating shaft 46 which, during pipe wrapping operation, very slightly moves the cam 41 in the direction of the arrow shown in Fig. 3 into brake releasing position against the resistance of the brake I actuating spring-pressed pin 48. A rigid bar link could be used instead of the spring 6|, however, I prefer to use a spring link as it absorbs any slight shocks due to any possible variations in the speed of the sprocket IS.

The strip tension control means includes, in addition to the arms 51, 59 and 60, selectively adjustable main tension control means consistingof a rod 62 which is slidably carried in a sleeve 63 pivotally secured to the reel carrier plate 26. One end of rod 62 is adapted to be pivotally adjust-ably connected to arm 59 by a pin insertable therethrough into one of the holes 59' in the free end of arm 59, the other end of rod 62 is screw-threaded for a wing nut 64 and extends through the convolutions of a helical compression spring 65 which is confined between the wing nut 64 and one end of the sleeve 63., A stop 66in the form of a collar is securely fastened to the rod 62 to 1mm the inward movement of rod 62 permitting, however, an outward movement thereof when the pull of the unwound strip portion 52 passing over roller 54 tends to swingthe arms 54, 59 and 68 about their pivots in the directions indicated by the arrows in Figs. 2 and 3 during the spiral wrapping of the strip material about the pipe 22 as the machine travels longitudinally of the pipe line, or during the movement of the pipe through a stationary type of machine.

Prior to starting the machine, the strip wrapping material is pulled from each supply roll 52 and fastened in any convenient manner around the pipe 20. As the rin sprocket I9 rotates and the machine advances along the pipe line, the wrapping material will be laid along the pipe in spirals which can be made to overlap to any extent desired by adjusting the speed of rotation of the ring sprocket l9 relatively to the speed of movement of the machine along the pipe line and by adjusting the angular positions of the members 28 relatively to their supporting lugs 24 on the sprocket l9. The entire reel carrier units are also adjustable rotatably relatively to the members 28 through the rotation of their tubular portions 28 within the supporting sleeves 30 of the carrier plates 26, and when the connection members 28 and the planes of the carrier plates 26 are adjusted to their desired relative angular positions the connection members 28 may then be secured in such adjusted positions in sleeves 30 by means of the set screws 61.

In order to accommodate rolls of strip material of varying widths the hub 32 may be extended longitudinally, as shown in Fig. 7, by the addition thereto of an extension hub 32'.

It will now be readily apparent that my improved means for constantly maintaining a uniform tension on the unwound strip portion not only prevents undesirable free unwindingof the wrapping material from the roll during the wrapping operation or while the machine is not in operation, but, my improved tension control means constantly automatically maintains a uniform tension on the unwound strip regardless of the gradually decreasing diameter of the supply roll and this is of considerable advantage as breaks or ruptures of the strip during wrapping operation are reduced to the minimum with the further advantage that substantial saving of time and lower cost of wrapping are affected over wrapping mechanisms heretofore employed where the machines had to be repeatedly stopped at frequent intervals during wrapping operations to permit necessary adjustments of the spring pressed devices employed to retain the supply rolls against free rotation and to maintain some tension on the unwound portion of the strip material.

In my improved mechanism the tension of the unwound portion of the strip of wrapping material is automatically maintained uniform due to the braking force of the brake shoe being automatically adjustably varied responsively to the pull exerted on the unwound portion of the strip to thereby maintain the tension uniform. By means of the coaction of the arms 51, 59 and and their coacting springs and 6| the pull on the unwound portion of strip material is maintained constant due to the slight braking action constantly imposed upon the brake drum and reel by the pressure of the spring-pressed brake-actuating pin against the free end of the brake shoe; the braking action of the brake-actuating pin at all times during the wrapping operation being maintained sufiicient to constantly exert a brak- 1 ing force against the brake drum and reel due to the very slight movement transmitted to the brake-releasing cam shaft 46 by the arms 51, 59 and fill and the counteracting springs 65 and 6 1.

Various modifications in the details of construction of the parts and members of my improved tension control means may be made by those skilled in the art to which my invention appertains without departing from the scope or spirit or the invention as defined in the appended claims Iclaim:

1. In pipe wrapping apparatus of the kind described, mechanism carried on a power-driven ring comprising a. reel. carrier plate detachably pivotally secured to and revoluble with said ring, a non-rotatable spindle carried on said plate, a hub rotatably mounted on said spindle, a reel removably mounted on said hub interlocked for rotation with said hub, a brake drum rotatable with said hubr a brake shoe Within said drum, adjustable spring-pressed means normally urging said brake shoe into braking position against said drum, a brake-releasing cam. operative to move said shoev into brake-releasing position, a brake control arm cperatively connected tosaid brakereleasing cam, and. means for constantly maintaining a uniform tension on a strip portion being unwound from the reel comprising a roller, over which said. unwound strip portion passes, pivotally carried on the free end of a pivot arm which is connected. at its opposite end with one end of a. pivot shaft rotatably carried on said plate, a strip tension control arm fixed to the opposite end of said pivot shaft, adjustable resilient means adjustably connected to the free end of said. tensioncontrcl arm yieldably resisting pivotal mouement. of said tension control arm, and link means operatively connecting said tension control arm with said brake control cam' for actuating said brake -releasing' arm.

2 In pipe wrapping apparatus as set forth in claim. 1 wherein said resilient means comprises a rod, slidably carried on said plate having one end. ad-justably connected to said. tension control arms sleeve in which said rod is slidably mounted carried. on said. plate, anut' threaded on the free end of said; rod, and a helical spring carried. on said rodhaving. one end in abutment with said not and its opposite end. in abutment with said sleeve.

3.. Inpipe wrapping apparatus of the kind described, mechanism carried on a power-driven ring comprising a reel carrier plate detachably secured to and revoluble with said ring, a: nonrotatable spindle carried on said plate, a hub rotatable mounted onsaid spindle; a reel removably mounted on said hub interlocked for rotation with saidhub, a, brake drum rotatablewith said. hub, abrake shoe within said drum, adjustable springpressed means normally urging saidbrake shoe into braking position against said drum, a brakereleasing cam operative to move said shoe: into brakeereleasing, position, a brake control'arm operativel-y connected to said brake-releasing cam, and means for constantly maintaining a uniform tension on-a strip portion unwound from the reel comprising: a roller, over which said unwound strip portion passes, pivotally carried on the free end ota pivot arm which is connected at its opposite end with oneend of a pivot shaft rotatably carried: on said plate, a striptension control arm mud. to the opposite end or said pivot shaft, ad-

justable resilient means adlustably connected to the free end of said tension control arm, and link means comprising a helical spring having one end adjustably connected to said tension control arm and its opposite end adjustably connected to said brake control arm.

4. In an apparatus of the character described. a power driven ring, a spindle projecting from one side of the ring, a plate mounted on the spin die for angular movements on the latter. means to secure said plate in any one or a plurality oi angular positions about the axis of the spindle, areel rotatable on the spindle and provided with a bralse drum facing the plate, a spring-pressed brake shoe mounted on said plate within the drum and in braking relation thereto, a shoe-releasins device mounted on the plate in engagement with the shoe, an actuator for said device mounted on the plate in position to deflect a strip portion be ing unwound from the reel, a connection between the shoe-releasing device and said actuator, and a spring thatyieldingly holds said actuator in the strip-deflecting position and allows the actuator to retreatwhenever the pull on the said strip por tkm-exeeeds a predetermined value.

5; In an apparatus of the character described, a power-driven rotatable ring, a spindle, means to secure said spindle-to one-side or the ring with its axis positioned in-any one of a plurality of angu lax positions in a plane at right angles tothe plane-of thering, a plate mounted on the spindle for angular movements about the latter, means to secure the plate in any one o! a plurality of positions anguiarly of the spindle, a reel rotatable on said spindle and provided with a brake drum facing said plate, a spring-pressed brake shoe mounted on the plate within and engaged with the drum, a shoe-releasing device mounted on the plate in engagement with said shoe, and an actuator for said. device mounted on the plate in the path of a strip being mountedirom the reel.

6. In an apparatus of the character described, a power-driven rotatable ring, a spindle, means to seeuresaid spindle to one side of said ring with its axispositionedin: any one of a plurality o! angular positions in a plane at right angles to the plane of the ring, a reel unit mounted on the spindle'tor angular movements about the latter, meansto secure said unit in any one o! a plurality of angular positions about the spindle, said unit comprising a supporting plate and a reel that is rotatable on the spindle, coasting brake meanstor said. reel carried on'said splndleand on said reel, and brake control means including a part movably mounted on the plate, remote from the spindle,- in position toengage and deflect a strip portion that is being unwound from the reel.

HENRY LUNGSTROM.

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